Suspension bridge



1945- w. c. WHlTNALL 3,

SUSPENSION BRIDGE Filed Dec. 2'7, 1945 INVENTOR Patented Feb. 6, 1945 UNITED STATES PATENT OFFICE SUSPENSION BRIDGE William Cox Whitnall, Mount Vernon, Wash. Application December 27, 1943, Serial No. 515,698

3 Claims.

My invention relates to improvements in the manner of stiffening suspension bridges by means of cables or chains; the objects of my improvement are, first, to provide adequate bracing and stiffening to the bridge, and second, to provide a means of equalizing the tension in all cables arising from loading or from contraction and expansion of the materials of which the structure is composed. I

I attain these objects by the mechanism illustrated in the accompanying drawing, in which Figure 1 is an end view and Figure 2 a side view of the main span of the bridge; Figure 3 is a view of the tension equalizing device, which is placed at the ends of the floor beams.

Similar numerals refer to similar parts in the several views.

No. l is the location of the cable anchorage; No. 2 is the load cable; No. 3, the hangers from the load cable; No. 4, the floor beams; No. 5, links from stifiening cables; No. 6, the stifiening cables; No. 1., the point of anchorage of the stifiening cables; No. B, the equalizing arm; No. 9, the base and bearing for said arm; No. I is a hydraulic cylinder, with packing nut for piston rod, filled with heavy oil or hydraulic fluid, and at tached to No. 4, the floor beam; No, II is a piston and rod operating in cylinder No. In; No. [2 is a compression spring.

The operation of the stiffening cables, No. 6, which may be laterally crossed as shown, or con nected to adjacent ends of floor beams, is to prevent vertical, lateral and torsional deformation of thedeck due to loading or extraneousforce, and to save considerable material over the conventional designs.

The operation of said tension equalizing device is as follows:- Piston No. II fits somewhat loosely in cylinder No. 10, allowing a gradual rise in the floor beam due to shortened cables as the temperature declines, but said piston is yet tight enough to prevent any sudden application of load or forcefrom altering the position or alignment of the deck system. Spring No. [2 takes up the slack due to lengthening of cables.

I claim:

1. A suspension bridge comprising a roadway, suspension cables, hangers extending from said cables to the roadway, other cables below said roadway, ties extending from said other cables to said roadway; and levers pivoted to said roadway, said hangers and said ties so arranged as to tend to maintain the same relative tension in all said cables under varying load and temperature conditions.

2. A suspension bridge consisting of suspension I cables and hangers therefrom to the roadway and inverted oatenary cables under said roadway with ties therefrom extending to said roadway, the said hangers from said suspension cables acting as fulcrums of levers upon which the weight of saidroadway is balanced by the downward pull of the said inverted cables through their ties.

3. A suspension bridge as in claim 2 in which at least one of the levers is connected to a hydraulic system comprising a piston within a cylinder' which acts to restrain suddenmovements of the lever relative to the roadway.

WILLIAM COX WHI'INAIL. 

